An experiment: keep it in OL using DVT, does it keep running...? And then return control to ECM and see what it does.

You're alluding to ECM being faulty, do you have a spare one to try...?

 

This may be tune related (but usually it's the other way around)... but the spark plugs being different is a physical problem...

when it fails to refire does scantool read RPM while cranking, and do you still get spark/spray everywhere...?

And is rail pressure still within spec...?

How about battery voltage wrt to chassis ground and wrt engine ground...?

Does scantool indicate VAT enabling (one of the STATEnn pids)...?

 

I've got to try forcing open loop again. Not sure I did that correctly last time.

I do not have a spare ECM. This one worked fine on the last motor and I have not had an error in flashing it but I suggested it because others have had the problem.

Agreed the tune is probably less than likely now since it is one cylinder. Reaching...

I'll double check RPM being read but I am almost certain it is reading during cranking.

Rail pressure is in spec from the moment the key is turned to on to after the engine dies. Not a rail pressure issue that I can tell. I might hook a gauge to the rail if I can get at the fitting (I flipped the rail to clean up the engine bay).

I'll have to get readings at the ground points though they are all perfectly clean and tight.

Not familiar with "VAT enabling (one of the STATEnn pids)." I'll research that a bit.

Thanks Joe!

 

VATS (vehicle anti theft system):

when it fails to start, check one of the STATEnn pids (? I think STATE05) to see if the pCM is indicating that VATS has kicked in, which if it did it would prevent starting)(also, I'm not 100% sure how this has been implemented on the 5th Gen Camaro).

 

( did you find debris in that one injector...? )

 

When engine dies at temperature, with scantool check ECT and IAT temperatures.

 

I'll check it when I get home. I believe I have seen this pop up before with other Camaro owners though I would have thought it would prevent starting and running completely.

Have not checked yet. Will do so tonight.

ECT has always been between 140-160 when the stumble gets bad. IATs have been 75-95 depending on how long the car ran.

 

Battery ground voltage was checked at all engine grounds and the body ground in the trunk in static (non-running). There were no issues. All grounds read same 12.58 volts. I should check them with the car running I suppose but it's getting harder to keep it that way for long.

I have not logged VAT. The "state **" PIDs all say unsupported.

I found no debris in injectors or rail. I swapped injector 8 with injector 4 and the problem did not move.

Latest log the car died with IAT at 88 and ECT at 115.

Next step is compression test all cylinders. I'll post the results tomorrow if I get it done by then. Thanks.

Travis

 

What about a bad crank or cam sensor?

Possibly need to do. C.A.S.E. relearn?

Travis

 

Possibly...

which reminds me: check crank end play.

 

But if that were the case (CKP) then scantool would show either zero or wrong rpm during cranking... but check it any way.

 

It looks like lifters were contaminated and not bleeding off properly which held the valves open. The problem materialized rather quickly and got progressively worse as the engine was run. Ultimately, I ended with only three cylinders having good compression and two that were completely dead. Pulled the heads off Saturday and two of the cylinders looked as though they never even fired. Of course all the extra fuel being dumped in the banks meant those doing the work were super rich. Those pistons were gummed up pretty good.

New lifters are in route as is a PurePower Stainless Steel reusable filter. A lot of folks will say that is a waste of money and it very well could be. Here's why I decided to go this route.

-I've got a buddy who runs them on a road track and swears by them. In the military we use them in a lot areas were filtration performance is a concern.
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